Film projecting apparatus



Nov. 15, 1938, VOIGT 2,137,070

FILM PROJECTING APPARATUS Filed July 16, 1936 3 Sheets-Sheet l INVENTOR Wdheim l/oiq' H15 AT Z QNEYS Nov. 1 5, 1938 w. VQIGT 2,137,070

FILM PROJECTING APPARATUS Filed July 16, less a sheets-sheet 2 Fig. 2

Wilhelm Vo algt 'INVENTOR ms ATTORNEYS Nov. 15, 1938. w, VOIGT 2,137,070

FILM PROJECTING APPARATUS Filed July 16, 1936 3 Sheets-Sheet 3 Wail/26m V0598 INVENTOR BYWA'W v vH l 5 ATTORNEYS Patented Nov. 15, 1938 UNITED STATES PATENT OFFICE assignor to Kalle & Co. Aktiengesellschaft,

Wiesbaden-Biebrich, Germany Application July 16,

1936, Serial No. 90,842

In Germany July 16, 1935 4 Claims.

The present invention relates to film projecting apparatus.

In the usual film projecting apparatus, grippers employed for the intermittent feeding of the 5 fllmare positively controlled by means of solid mechanical devices. As a consequence of this care must be taken when inserting the film in the projection window that the gripper is located in such position that it engages with a perforation of the film when the apparatus is set in operation. This requirement can, however, only be fulfilled sufficiently reliably with great difilculty. If the forwardly moving gripper, however, fails to engage the perforation of the film, damage to the latter is unavoidable.

Now it has been found that the film can be set forward with certainty without the danger of damage if the gripper, which may, for example, be made in fork shape, is fixed to the piston of a small pressure cylinder which is moved up and down along the film. The gas supply to this cylinder is regulated by suitable control members, for example the slide valve gear known in connection withsteam engines, in such manner that the gripper engages with the perforation of the film during the time in which the cylinder moves in the direction of movement of the film.

The cylinder piston must accordingly immedi-- ately before or at the commencement and immediately after or at the termination respectively of the cylinder movement, be moved towards the film and away from the film respectively. During the time in which the cylinder is moved in the opposite direction to the direction of movement of the film, the gripper releases the said film. By the employment of a gripper drive of this kind, it is rendered possible to insert the film in the projection window without particular precautions. If, for instance, the gripper does not immediately engage with a perforation of the film, then, because of the action of the elastic air buffer, the said gripper slides along 'the film without causing damage thereto until it engages with the perforation.

The movement of the pressure cylinder itself may be brought about in various ways. The said movement may also be controlled by means of gas pressure by arranging the cylinder on the piston of another pressure cylinder. The gas supply to the two cylinders may then take place through the same control member, so that the movements of the two pistons and consequently the. horizontal and the vertical movements of the gripper, are positively coupled. A further pos- 66 sible arrangement for the movement of the pressure cylinder containing the gripper piston is hereinafter described. The remaining movable parts of the apparatus, for example, guide drums and the like, are also preferably moved by gas pressure. 'In this way, almost noiseless running of the apparatus is obtained, which is very important, particularly for home kinematographs especially in the projecting of sound films. As the driving gas it is preferable to employ compressed air, which can be produced by means of a simple bulb of rubber, bellows or the like. The supply of the compressed air to the apparatus is effected by means of thin rubber tubes. In this way a drive which is free from vibrations is rendered possible. It is naturally possible to substitute for the compressed air any other desired gas or even vapor for driving.

A constructional form of a film projecting apparatus according to the invention is illustrated by way of example in the accompanying drawings, in which:

Fig. 1 is a longitudinal section through the projecting apparatus,

Fig. 2 is a plan thereof,

Fig. 3 shows a front view of the apparatus with the casing removed, and

Fig. 4 shows a section taken on line 44 of Fig. 1.

Referring to the drawings:

Reference numeral I denotes a draw-off spool carrying the film which is to be projected. This spool is slidably mounted on the axle II, which is journalled in a bore of the arm IS. The said arm is fixed to the baseboard IQ of the apparatus. The film 20 runs from the draw-01f spool I over the toothed guide drum 2, meanwhile passing in front of and behind the said drum respectively over small guide rollers 2|. The film then runs in a loop over the rounded off upper wall of the housing 43 and is thereupon led past the projectinggwindow by means of the guide plate 22, the edges of which are turned over and form guide bars for the edges of the film. The gripper tooth l4 engages through a recess in the guide plate with the film perforation. The film is after the projection led back overthe toothed drum 23 on to the winding .up spool 24. The said spool is mounted so as to be slidable on the axle H. The aforementioned toothed drums are mounted on an axle 53 rigidly with the worm wheel 25 and are driven by means of the'worm 2 On the toothed drum 23 a cord pulley 21 is a so arranged which drives the winding up spool 24 connected with the pulley 29 through the medium of a cord or chain 28. The turning knob 33 serves for overcoming the dead point when starting up the apparatus.

The objective employed is represented diagrammatically at IS. The reference numeral l5 denotes a lamp and 30 a reflector. 3| is a lens arranged in the mount 32, which lens throws the light emitted from the lamp in a bundle of rays on to the film located in the projection window. The lamp |6 is mounted in the holder 54. The current supply leads 55 and 55 are separated from one another and from the supporting arm 5'! by means of the insulating layers 58.

The driving mechanism proper is arranged on the how 34 fixed to the baseboard. The driving member is constituted by the cylinder 5 in which the piston 8 moves. The gas for driving the apparatus is led through the nozzle 35 into the slide valve housing 9 in which the slide valve Ill is arranged. In known manner, the said valve allows the driving gas to impinge alternately through the openings 36 and 31 respectively on the two sides of the piston 5. The exhaust gas is discharged again in known manner through the openings 38 and 39 respectively.- The piston 6 is connected by means of the piston rod 1 and the link 40 with the connecting rod 8 which is of frame-like form and drives the crank-shaft 3. From the said crank shaft 3 the slide valve I0, mounted on the link 42, is operated in known manner by means of the eccentric H and the connecting rod 4| which is likewise constructed of frame-like form. The driving mechanism of the shaft 3 is accordingly identical with the usual drive of steam engines, so that further detailed description is unnecessary. The shaft 3 is carried on the one side through the bow 34 and the wall of the housing 43 and is connected with the worm 25. On the other side, the shutter disc 4 is fixed on the axle.

The fork-shaped gripper H is fixed to the piston l3 by means of the piston rod 44. The piston i3 moves in the cylinder i2 and receives its driving gas through the conduits 45 and 59. The gas supply to the cylinder i2 is regulated by means of the same slide valve which regulates the gas supply to the cylinder 5. The supply of the gas is effected through the bores or ports 45.

The cylinder I2 is fixed to the plate 41, which in turn is fixed in the frame 48. At the upper end of this frame the axle 50 which carries a roller 5| is journalled in a projection 49. The said roller runs in a heart-like shaped curved guide 52 arranged in the shutter disc 4. During one rotation of the curved guide, the gripper is moved once up and down. The curved guide is so adjusted that during the feeding of the film the picture is screened off by the vanes of the shutter.

The supply conduits for the driving gas to the cylinder l2 are arranged by suitable location of the bores 46 in such manner that the piston I3 has been moved forward towards the film when the cylinder 12 moves downwards.

The operation of the apparatus illustrated in the drawings is as follows:

At the beginning, the piston 6 is in its highest position in the cylinder 5. The shutter disc is so located on the axle 3 that the roll 5| is in the position I relative to the curved guide 52. Owing to this position of the roll 5|, the cylinder I2 is also in its highest position. The piston |3. is located on the right side of the cylinder |2 (see Fig. 1), so that the gripper l4 does not engage with the perforation of the film. The operation may be divided for explanation into the following four phases.

1. The nozzle 35 is connected by means of the slide valve ||I over the openings 36 and 45 with the cylinders 5 and II, respectively, so that the stream of air fed through the nozzle 35 acts on the upper side of the piston 5 and the right side of the piston i3. The piston |3 moves to the left side, so that the gripper engages with the perforation of the film 20. During this time, the piston 5 moves somewhat down and the roll 5| moves from the position I to the position II. The cylinder l2 remains still in its initial position. The air in the lower part of the cylinder 5 and the left part of the cylinder i2 escapes through the openings 59 and 31, respectively, which are connected in this phase with the outlet opening 39. The shutter is open during this phase.

2. The piston 6 moves further downward until it has reached its lowest position. Owing to that movement, the roll 5| moves from the position II to the position III, and the cylinder l2 moves down. The piston i3 remains in the position it has assumed during phase 1, so that the film is drawn off. The shutter is closed during this phase.

3. The slide valve changes its position relative to the openings of the slide valve housing so that the air is led from the nozzle 35 over the opening 31 on the lower side of the piston 6. The room of the cylinder 5 above the piston 6 is connected over the opening 36 with the outlet opening 38. Simultaneously, the openings 45 and 59 are connected with the openings 38 and 35, respectively. The piston I3 is pressed to the right so that the gripper releases the perforation. During this time, the piston 6 moves somewhat upward and the roll 5| moves from the position III to the position IV. The cylinder l2 remains still in the position it has assumed during phase 2. The shutter is open during this phase.

4. The piston 5 moves further upward until it has reached its highest position and the roll 5| moves from the position IV to the position I. Owing to this movement of the roll 5|, the cylinder i2 rises. At the end of this phase, during which the shutter is closed, all parts have again reached their initial position.

I claim:

1. Film projecting apparatus, comprising a film guiding device containing a projecting window, an objective before the said window and a lamp behind the window, a driven axle above the said window, a shutter disc on this axle, the vanes of the said shutter disc being able to cover the said projecting window, a heart-like shaped groove in the said shutter disc, a roller which slides in the said groove and a rod connected with the said roller, the groove being so adjusted that during one rotation of the disc the rod is moved once up and down, a cylinder fixed at the free end of the said rod beneath the said projecting window so that the axis of the cylinder is vertical to the said shutter disc, a piston slidably arranged in the said cylinder, two openings in the said cylinder near the ends of the cylinder, a rod on the said piston penetrating the base plate of the said cylinder which is located opposite to the said film guiding device, a forkshaped gripper fixed to the said piston rod, a slide valve serving for regulating the gas supply to the said cylinder, which valve is driven by the said axle and so adjusted that the valve allows the gas to flow into the opening of the cylinder near the gripper side of the said piston,

guiding device that the gripper in the one end when the cylinder moves upward, and that the valve allows the gas to flow into the other opening of the cylinder when the cylinder moves downward.

2. A motion picture projection apparatus, comprising a film guiding device Containing a window, means for projecting a film in combination with the said window, a pressure cylinder arranged near the said guiding clevice and beneath the said projecting window with its axis perpendicular to the plane of the said projecting window, a piston slidaoly' arranged in the interior the said cylinder, a rod on the said. piston penetrating one of the base plates of the said cylinder through a bore, a gripper fixed on the free one. of the said piston red, the cylinder being located at such a distance iron: the said guiding (lGllCE that the gi'ipgoer in the one end position of the piston can engage with the perforation of a film arranged in the said guiding device, means serving for moving the cylinder up and down parallel to the said guiding device, and means for alternately leading a gas onto the sides of 1? onto the sides of the said piston, a rod on the said piston penetrating one of the base plates of the said cylinder through a bore, a foils-shaped gripper fixed on the saisl piston red, the cylinder being located at such a distance from the said position ofthe piston can engage with the perforation of a film arranged in the said guiding device, means serving for moving the cylinder up and down parallel to the said guiding device, and a valve connected with the said cylinder adapted for regulating an alternating gas supply to the said openings of the cylinder.

4. A fllm projecting apparatus, comprising a film guiding device containing a projectingwindow, an objective before the said window, a. lamp behind the window, a pressure cylinder arranged near the said guiding device and beneath the said projecting window with its axis perpendicular to the plane of the said projecting window, a. piston slidably arranged in the interior of the said cylinder, two openings in the wall of the said cylinder serving for leading a gas onto the sides of the said piston, a rod on the said piston penetratlug one of the base plates of the said cylinder through a bore, a. fork-shaped gripper fixed on the said piston rod, the cylinder being located at such a distance from the said guiding device that the grlpper in the one end pcmition of the piston can engage with the perforation of a film arranged in the'said guiding device, means serving for moving the cylinder up and down parallel to the said guiding device, a slide valve connected with the openings of the said cylinder adapted for regulating the gas supply to the cylinder, the said valve being coupled in such a; way with the cylinder moving means that the valve allows the gas to flow into the opening of the cylinder near the gripper side of the said piston when the cylinder moves upward, and that the valve allows the gas to flow into the other opening of the cylinder when the cylinder moves downward.

WILHELM VOIGT. 

